Sponge Divers Pulled a 2,000-Year-Old Computer From the Aegean

Around Easter 1900, Captain Dimitrios Kondos and a crew of sponge divers from Symi were waiting out bad winds off the Greek island of Antikythera when they decided to dive for sponges to pass the time. At 45 metres, in waterproofed canvas suits and copper helmets, they found a Roman cargo ship instead. One diver came up babbling about a heap of dead naked people on the seabed. They were marble statues.

The Hellenic Royal Navy spent the next year hauling up bronzes, pottery, jewellery, and coins. In July 1901, somewhere in the haul, was a corroded lump of bronze and wood roughly the size of a shoebox. Nobody paid it much attention. The bronze had oxidised into atacamite, which cracked and shrank as it dried, and the lump split into pieces on a museum shelf in Athens.

On May 17, 1902, the archaeologist Valerios Stais was looking at one of those pieces and saw a gear tooth.

That shouldn't have existed. Greek antiquity was not supposed to have produced precision gearing — that was a medieval European invention, the kind of thing that drove cathedral clocks. Stais's identification was politely ignored for fifty years. Then in the 1950s the British physicist Derek de Solla Price talked the museum into x-raying the fragments, and the gears kept multiplying. Modern imaging has now mapped at least thirty interlocking bronze wheels inside the original 34-by-18-centimeter case, with inscriptions describing the bodies they tracked.

The device predicted solar and lunar eclipses, modelled the irregular motion of the Moon, and counted down the four-year cycle of the Olympic Games. Best dating puts it in the late second or early first century BC. The shipwreck itself sank around 70 BC, which means the computer was already an antique when it went under.